What is the term for the loss of water from a plant through its leaves?

• A. Transpiration
• B. Condensation
• C. Evaporation
• D. Respiration

Answer: (A)

Transpiration is the loss of water from a plant through its leaves. This happens when water moves from the roots up through the xylem to the leaves and evaporates from the leaf surfaces, mainly through tiny openings called stomata. Opening the stomata for gas exchange lets in carbon dioxide for photosynthesis, but it also allows water vapor to escape, creating a pull that helps draw more water up from the roots. This water loss helps transport nutrients and cools the leaf. Condensation is water vapor turning into liquid, not a loss from the plant. Evaporation is a general term for liquid turning into vapor and can occur from many surfaces, whereas transpiration is the plant-specific form of water loss that occurs through the leaves. Respiration is the metabolic process that releases energy from sugars, using oxygen and producing carbon dioxide and water, not mainly about water loss through leaves.